Last week, the killer of 21-year-old British backpacker Grace Millane was sentenced to life imprisonment with a minimum 17-year non-parole period. Millane had been strangled to death before her killer snapped photos of her corpse, shoved the remains in a suitcase and buried her body in the woods.

While the Courts of New Zealand determined that “the circumstances of the murder showed a high-level of callousness, including: the intimate nature of the murder itself,” the defense painted Millane’s violent death as the accidental result of consensual rough sex gone too far. According to Millane’s killer, his victim enjoyed rough sex while he was “new to all that stuff” and couldn’t tell things had gone too far. (Later testimony from another near-victim suggested Millane’s killer had more familiarity with violent sex acts than he claimed.)

This kind of defense, dubbed the”50 Shades defense,” after the popular series of BDSM novels, has become increasingly common in recent years, CNN reports. Men turning to these defenses claim a woman’s violent death was the unintended result of consensual rough sex, thereby eliminating intent while also shifting blame to the woman, who, as The Cut noted, often has the intimate details of her sex life dragged into the courtroom as evidence used to justify her murder.

According to CNN, at least 60 UK women have been killed in episodes of sexual violence defended as consensual sex since 1972, with 18 women dying in the past five years. Meanwhile, the defense is also gaining global popularity, with We Can’t Consent to This founder Fiona Mackenzie telling CNN the group maintains “a list of around 250 women who have been killed in various countries around the world by men who claim at some point that they consented to it.”

The growing popularity of the 50 Shades defense reflects a greater culture of victim-blaming that dominates broader discussions of sexual violence. “Women are blamed for their behavior,” Toni Van Pelt, president of the National Organization for Women (NOW), told CNN. “Their sex lives are always questioned — whether or not they are sexually active, and what kind of sexual activity do they participate in, and were they drinking — these things that have nothing to do with what’s happened to them.”